Atmosphere Ocean Science Friday Seminar

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A Simulation of Beaufort Gyre Interior Mixing

Speaker: Hassan Mason, CAOS

Location: Warren Weaver Hall 1314

Date: Friday, May 3, 2024, 4 p.m.

Synopsis:

The Beaufort Gyre (BG) is a basin scale anti-cyclonic ocean gyre in the Arctic ocean. While past research claimed the BG is not baroclinically unstable due to sea ice induced surface drag, a recent linear stability analysis with modern observational datasets suggests the opposite. That is: the BG interior contains a rich isopycnal structure that is subject to baroclinic instability despite sea ice induced surface drag. I will present an idealized MITgcm simulation forced by BG state estimates to model the turbulent eddy field induced by its baroclinically unstable mean state. The simulation features a zonal re-entrant channel with a mean state zonal jet and mechanically active sea ice. Because the interior density structure drives the dynamics, this simulation requires and uses a channel mean forcing that is reminiscent of stratified QG and common within geophysical turbulence simulations. The model output shows remarkable agreement with available BG observations and therefore supports local baroclinic instability as a generation mechanism for BG eddies and as an important driver of BG dynamics. Additionally, the output provides some insight on the behavior of an ice free BG